1. Field of the Disclosure
The disclosure relates to welding sheets of material and more particularly the disclosure relates to welding sheets of material by means of fiber lasers.
2. Prior Art
The laser welding technique requires a close contact between workpieces to be welded together. Furthermore, the contact should be maintained so that a thermo-load, which is a by-product of welding process, was uniformly distributed in the welding region. Otherwise, the pieces to be welded would be deformed. A few approaches concerned with the contact and thermal aspects in a laser welding process are known and discussed herein below.
The EP1219384 discloses a laser-welding head for coupling workpieces to one another. The head includes a pressing device, having a roller which moves along parts of respective workpieces near a weld line to press together the workpieces, and a pressing unit for applying a predetermined pressure to the parts near the weld line. The welding is realized by displacing the roller only along linear paths. Often, the roller leaves a scratch on the surface to be treated. Also, the velocity of the roller is not high.
The US patent publication US2005279448 also discloses a pressing unit configured to press the workpieces to be welded towards one another. The pressing unit is made from transparent material to allow a laser beam to propagate through the unit. The pressing unit is fixed to the workpieces and should be constantly readjusted.
There is a need therefore to provide a contactless laser-based method for welding workpieces that are held together without the use of the pressing units.
A further need exists for a contactless laser-based welding process providing a laser head with displacement along a variety of paths at a relatively high velocity.